Preheat your oven to 350 degrees and prepare a baking sheet with parchment paper
In a large mixing bowl combine blueberries, sugar, cinnamon, lemon juice, and cornstarch and mix until the blueberries are well coated.
Take your thawed pie crust and lay it out on the baking sheet. Place the blueberries in the center of the crust leaving about 2-3 inches around the sides.
Fold the crust over the berries all the way around. (see photos)
Whisk one egg in a small bowl and using a pastry brush, brush the top of the pie crust, sprinkle the crust with about 1 tbsp of sugar.
Bake at 350 for about 20 minutes or until the curst is golden brown. (check it after 15 minutes)